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Monday, May 21, 2012

Food Choice: Disgust, pain and preferences

Food choice is a
complex issue. At one level, we share the same biology as all animals as
regards hunger, appetite and satiety. Rat studies can thus explain some of the
mechanisms but they fall far short of the bigger picture because humans have a
large and very complex frontal cortex, which governs all the things that make
us human and not rats. It is through the cortex that we think, learn, speak and
assimilate and disseminate complex ideas. More than anything else, these
attributes allow us to divide labour and live in a sophisticated society and
that society itself plays a major role in food choice.

In lecturing my
students on food intake, I ask them to close their eyes and to think of some
occasion when they were really hungry. I then tell them that when they open
their eyes, the PowerPoint slide will show a food and I want to know would they
eat it. Invariably, they indicate
their refusal to consume the food, which is a very nice bowl of highly
nourishing and succulent cat food. They do agree that if the choice was between
staying alive and eating the cat food, then they would eat it and just hope not
to gag. Having recently read “How Pleasure Works” by the Yale professor of
psychology, Paul Bloom, I now know that the reaction of my students is one of disgust.
I also learned from Bloom that disgust is not a property of the cat food but a socially
conditioned belief. Quite simply, I know of nobody and, dear reader, I would
bet you know of nobody, who eats cat food. The cat food is nutritious, safe,
made from high quality ingredients by branded companies for highly fussy pet
owners. So there is nothing inherently disgusting in cat food. It’s simply a
disgusting thing to eat by our social norms. Rats would have no qualms in
eating cat food. Eating insects is disgusting to us but not to many nomadic
tribes and eating pork is disgusting to a devout Muslim but not to the majority
of Irish people. Paul Bloom goes on to point out that whereas society decrees
what is acceptable to eat, within that framework, individuals can show disgust
or more correctly, aversion to specific foods and, in general, such aversions
can be related to some life experience. Thus I like fish but if given a choice,
I would not eat mackerel. I still recall the stink in our kitchen at home when
my father would head, tail, gut and fillet a bucket of mackerel for grilling,
which he and his mates had caught in Dublin bay.

Bloom also
raises another aspect of social influence on food choice: pain. Now it might
seem strange to write about pain in a book on pleasure but so long as the
recipient is in control of the situation, mankind likes a little bit of pain.
We go to horror movies, which can be terrifying and we take amazing risks on
crazy rides in amusement parks. In foods, we eat chilies and although our taste
buds tell us not to do so, we overcome these because society decrees some
consumption of chilies to be worthwhile. Thus in Mexico, where chili
consumption is high, children are gradually weaned on to a high chili diet.
Such a diet in earlier times helped give an identity to a group in much the
same way as their language, music or dance did. You can imagine the fun these people
had when a stranger was given their hospitality only to scream for water to
cool their burning palates!

Let us now
return to the physiology of taste and flavour and see how that competes with
social pressure. Paul Bloom draws on a joint study carried out by the business
schools at MIT and Columbia. Subjects were asked to taste two beers: a regular
Boston brand or a “new” MIT beer. The latter was no more than the regular
Boston beer with a dash of balsamic vinegar. The first group (the control
group) were not given any information at all and simply asked which brand they
preferred. They voted 60:40 for the “new” MIT beer The second group were told
that the regular Boston beer was to be compared to a “new” MIT brew and they
were told that this beer was just the regular beer plus balsamic vinegar. Now
the vote was only 20% for the MIT brew. A third group was treated like the
control group but immediately after they had drunk it and before they expressed
their preference, they were told the truth: that the “new” MIT beer was just
ordinary beer with balsamic vinegar added. They voted like the control – 60%
preferring the MIT brew. Clearly, the latter group, like the controls, formed
an opinion that if a beer came out of MIT it must be good. Having now made
their minds up, the third group stuck to this assumption even though they knew
that it was just a stupid concoction. The values we give to foods in making
food choice are very complex. The idea that a beer from MIT had to be good goes
hand in hand with our preferences for brands. Indeed, Bloom points out that
studies show that Coca Cola drinkers enjoy Coke more when the glass is a Coke
branded glass. Status is very important in food choice because, like the
peacock’s tail, it is a symbol of ones power and status.

Rat studies are
thus of limited use in understanding food choice. They might explain the mechanisms,
which determine the desire to eat but not food preferences. They are socially
determined to a great extent. The simpletons of public health nutrition reduce
the obesity issue to a higher probability of choosing some food such a sugar
sweetened beverages or fast food because that’s the simpleton’s fashion –
simple and stupid. Some people make the conscious decision to take up smoking
or alcohol intake. But nobody wakes up and says:” Guess what. I’m going to get
fat”. It happens and we know so little about how that passive accumulation of
energy occurs and how our food preferences promote this weight gain. We need
less research money spent on studying why rats chose to eat or not and more
money spent on human behavioural sciences, particularly food choices and
preferences.

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"Ever seen a fat fox ~ Human obesity explored"

About Me

I graduated from University College Dublin in 1971 with an Masters in Agricultural Chemistry, took a PhD at Sydney University in 1976 and joined the University of Southampton Medical School as a lecturer in human nutrition in 1977. In 1984 I returned to Ireland to take up a post at the Department of Clinical Medicine Trinity College Dublin and was appointed as professor of human nutrition. In 2006 I left Trinity and moved to University College Dublin as Director of the UCD Institute of Food and Health. I am a former President of the Nutrition Society and I've served on several EU and UN committees on nutrition and Health. I have published over 350+ peer reviewed scientific papers in Public Health Nutrition and Molecular Nutrition and am principal investigator on several national and EU projects (www.ucd.ie/jingo; www.food4me.org). My popular books are "Something to chew on ~ challenging controversies in human nutrition" and "Ever seen a fat fox: human obesity explored"